1. Technical Field
This invention is directed to a process of manufacturing artificial logs for use in gas equipped fireplaces to give the impression of real burning logs.
2. Description of Prior Art
Prior art processes for artificial log manufacturing typically use a screen mold with textured surface elements on the screen that is form fitted into an apertured support mold cavity into which a slurry of mineral or ceramic fibers is deposited. A vacuum is then applied to the mold drawing the liquid therefrom, leaving the mineral fibers collected on the screen surface. The log is removed from the mold and dried in an oven to eliminate the remaining moisture present after molding of approximately 50%. After an extended drying time in the oven the log is removed and color coded for realism and then redried ready for use. See for example U.S. Pat. Nos. 4,877,417, 5,271,888, 5,284,686, 5,612,266, 5,700,409 and 5,800,875.
In U.S. Pat. No. 4,877,417, an artificial fireplace log is disclosed which is partially combustible having a clay carrier and consumable wood fiber portions.
U.S. Pat. No. 5,271,888 is directed towards a ceramic log molding process for forming lightweight synthetic ceramic logs having a flexible porous pattern screen using a vacuum source for withdrawing water from the mold slurry forming a log representation within the mold.
A combustible artificial log is disclosed in U.S. Pat. No. 5,284,686 having a composite log formed of ceramic concrete with ceramic fiber sections.
U.S. Pat. No. 5,612,266 shows a decorative non-combustible synthetic fire log formed my mineral foam in a mold shape as a nature wood log. The mineral foam composition is claimed.
U.S. Pat. No. 5,700,409 discloses a method of molding an article in which a flexible mold having an article forming cavity is affixed to a suction chamber so as to release their article within the mold after the molding process.
Mineral fiber log processing is disclosed in U.S. Pat. No. 5,800,895 wherein a screen mold is used to impart an exterior log surface. A slurry containing mineral wool fibers is drawn into the mold by a vacuum leaving the mineral fibers within the mold.
Alternate prior art patents have been directed to improvements to artificial logs with enhanced glowing properties by having inserts of refractory and ceramic fibers that have a higher thermal conductivity component compared to the surrounding materials. When heated, these areas will glow at a lower temperature thus imparting a naturalistic feature to the log, see for example U.S. Pat. Nos. 4,877,417, 5,026,579, 5,069,200, 5,284,886 and 5,688,568.
In U.S. Pat. No. 4,877,417 an artificial fireplace log is disclosed having a clay carcass and a combustible wood fiber material outer layer.
U.S. Pat. No. 5,025,579 is directed to a composite artificial log where the log is formed from a ceramic concrete upper section and a ceramic fiber lower section having a lower thermal conductivity.
U.S. Pat. No. 5,069,200 discloses a gas fired artificial log assembly having the logs stacked with contoured gas burners positioned within. Portions of the logs are made of ceramic fiber inserts that react to heat impingement.
U.S. Pat. No. 5,284,686 claims ceramic concrete logs with ceramic fiber sections that act as inserts for enhanced visual appearance.
U.S. Pat. No. 5,688,568 defines a ceramic fire log process wherein a portion of the pre-formed log's surface is loosened to provide a texture and less dense area resulting in a more naturalistic log. The loosening of the fibers is achieved by manual stimulation or abrasion.